Electromagnetic relay



Feb. 13, v T. BAKER 2,359,331

ELEGTROMAGNETI C RELAY Filed June 50, 1941 I INVENTOR GEORGE THOMAS BAKER ATTORNEY Patented Feb. 13, 1945 ELECTROMAGNETIC RELAY George Thomas Baker, Liverpool, England, as-

signor, by mesne assi Electric Laboratories,

gnments, to Automatic Inc., Chicago, 111., a corporation of Delaware Application June 30 1941, Serial No. 400,519

In Great Britain July 18, 1940 22 Claims. (Cl. 200-104) I The present invention relates to electromagnetic relays particularly of the kind which are .used in telephone and like signalling systems. Such relays usually consist of an electromagnet consisting of a straight core with winding, 2. heel piece and an armature pivoted with respect to the heel piece and a bank of contact springs mounted on the back of the heel piece and arranged in various combinations depending upon the use to which the relay is to be put, which contact springs are operated by the movement of the armature. Such a construction of relay has certain disadvantages. From the manufacturing point of view it is necessary to assemble a large variety of contact spring combinations to cater for the different uses to which the relays are put and the number and nature of spring combinations required. Furthermore the various contact springs require to be individually adjusted which due to the bank formation is liable to affect the adjustment of other contact springs so that the greater the number of contact springs the more is the adjustment required. A further disadvantage is the irregular shape of the relay which does not conveniently lend itself to protection from dust by a cover and in particular by a cover which can be hermetically sealed, so that the contacts may operate in an enclosed chamber and in a non-oxidising atmosphere. Another disadvantage of the present construction is that the assembly involves a number of operations which result in individual adjustments being required to every relay, such adjustments being-dependent upon the degree of tightness with which screws are forced home as well as upon variations in thickness of the insulating members and the springs themselves. This necessitates considerable skill in the assembly of the relay to do this in a cheap and reliable manner.

The object of the present invention is to provide a construction of relay which enables the above defects to be largely. overcome and to this end according to one feature of the invention the component contact springs of each spring combination used in a relay are secured in position in separately detachable units preferably by moulding so that it is only necessary to stock a limited variety of spring combination units such as makes, breaks, changeovers, which can be combined in any order and number within the capacity of the relay.

According to a second feature of the invention which is particularly advantageous but is not exclusively limited to relays having a plucorrect relative positions by a final securing operation thereby reducing the securing operations, of which quite a number are required in the known type of relay, to a single operationv and in particular to an operation which does not call for further adjustment of the contact springs.

A further feature of the invention which while particularly advantageous for use in conjunction with a relay is not exclusively limited tohaving a plurality of moulded spring combination units and assembled within an embracing member or casing so as to reduce the securing operations required consists of arranging that the operating member or members of the contact spring combination moves in the same direction as and in line with movement of the armature. By this means it is possible for the spring combinations to be mounted in line with the core of the relay and secured in a tubular casing.

The protection of the contact from dust according to a subsidiary feature of the invention is effected either by moulding the individual spring combinations in capsules having flexible sides or moulding the spring combinations within a fixed annular member having flexible ends but including all the spring combinations required or providing a moulded cover for the relay, its armature and operating parts as well as for the spring combinations.

These and other features of the invention will be better understood from the following description of one method of carrying the invention,

into effect described with reference to the accompanying drawing comprising Figures 1 to 7.

Of these figures Figs. 1-4 show various views of one form of relay embodying the various features .of the invention although it will be understood that the invention is not limited to such a construction but extends to any relay construction falling within the scope of the appended claims, Fig. 1 showing a part sectional longitudinal view of the heel and of the relay assembled inside a moulded insulating case of tubular form each spring combination unit such as makes, breaks," change-overs," etc. being in the form of an individual capsule. Fig. 2 shows a sectional view through the line VW in Fig. 1.

Fig. 3 shows a sectional view of the armsture end or the relay, which view is taken at right angles to that of Fig. 1, that is to say, looking in the direction designated X in Fig. 1, while Fig. 4 shows a sectional view through the line YZ in Fig. 3.

Fig. 5 shows an enlarged semi-diagrammatic representation of a sectional elevation of a typical one of the capsules of the relay, while Fig. 6 shows a plan view of such a capsule in which for the purpose of showing the shape of.

the contact springs therein the upper flexible face or diaphragm is assumed to have been removed.

Fig. 7 shows a spider spring arrangement for enabling the relay armature to be centered without having to rely on the sides of the moulded case, so enabling friction to be reduced.

Referring now to Figs. 1-4, themain body of the relay comprises a moulded insulating tube ll which is closed at the left-hand end in Fig. 1, and which has a cap ll (Fig. 3) which when secured in position closes the other end. The case may be moulded of suitable material such as in any 01 the known synthetic resin materials and if preferred a transparent insulating plastic material may be employed instead so that the operatlon of the relay alter assembly and sealing may be observed at any time.

The whole re ay including the operating windlng, heel-piece, armature and capsule spring com bination units are assembled inside this tube which forms part of the structure of the relay and which serves to support the various components thereoi in the correct relationship to each other.

Before consideration is given to the mode of assembly of the relay, an examination will be made the contact spring combination units which when assembled within the case together form the spring-set build-up.

It will be understood that the various units are built-up as different standard items such as "makes, breaks," change-overs, make before break change-overs," so-called Y break or break last" units and so on. These items are stocked in the individual forms and are the same for all general purpose relays, the production of any such relay consisting of taking the appropriate contact units out of stock and assembling them as will be described later in the description.

As shown the units are in the form of capsules which can be individually sealed. the interior being either exhausted or filled with an inert gas but ii the tube III is sealed, there is no necessity for the individual contacts to be sealed and so the unit can consist of a structure without an enclosed chamber as will be readily appreciated. Alternatively th springs only may be kept in stock and the particular combinations required moulded in'position as a whole.

Considering now the construction of a typical capsule "make" contact unit such as is shown in Figs. and 6, it will be seen that this comprises an outer annulus I! which may be moulded from the same material as the relay case it), and two flexible end i'aces or diaphragms I3 and H which may be also 0! the same material but of sufflcient thinness to enable such movement as is required to close or to open the contacts, as the case may be, to be obtained with a minimum effort. Carried by the flexible end faces l3 and i4 is a cylindrical central pillar l5 which is also of moulded insulating material nd which is provided with a small projecting tongue l8 (Fig. 6) by means of which it supports the lower contact spring H. The two contact springs l1 and ii extend through and are sealed in the annulus H at a proper distance from each other and curve round on either side of the pillar l5, while they terminate in winding tags which are bent at right angles to the plane of the capsule. Botn springs are downwardly tensioned, spring l8 engaging with a moulded tongue in the annulus l2 and spring i1 engaging with the projection on the central pillar l5. Preferably the contact springs are moulded in position and can be individually adjusted. By suitably dimensioning the pillar or operating member I5 with respect to the annular or fixed supporting member I! for instance by making the thicknesses exactly equal the adjustment of the contact springs of each unit will be substantially independent of the adjustment of other secondary units on either side thereof.

When the pillar i5 is caused to commence to mov upwardly the diaphragms l3 and I4 distort and so allow this movement to take place and in so doing the pillar carries the spring 11 into contact with contact spring ill, the movement prior to contact being determined by the relative positions of the projector 16 on the pillar and the projection on th annulus ring l2. Similarly, when the upward pressure is removed from the pillar the tension on the springs assisted by any force which may be exerted by the distorted diaphragms causes the pillar to restore to the position shown in Fig. 5 when the contacts are opened.

In the case of a changeover combination the third contact spring required will be located below the spring H and will be tensioned upwardly against a second tongue which will be provided in the annulus l2. Other types of spring combinations will be dealt with in whichever manner proves most convenient.

Th assembly and construction of the difierent types of capsule units it is proposed to effect by machine from the component mouldings and contact springs. In particular the thickness of the outer annulus andcentral pillar in each case will be made as closely alike as possible so that ii a number of capsules are laid together as shown in Fig. 1, then the outer rings will form a virtually continuous tube and the pillars will form a contlnuous column. This ensures that all spring combinations are interchangeable with one another in the pile without the necessity for readjustment, and further ensures that spring combinations after having been taken from stock, can be assembled in a pile without there being any need for adjustment thereof.

Considering now the assembling together 0! the relay components, it will be noted from Fig. 5 that the connecting tags of the contact springs in the capsule which may be in rod or strip form are bent at right angles to the plan thereof, and the first part of the assembly is to drop the capsule contact units required into the tube l0 so that the connecting tags which locate in different longitudinal recesses in the walls of the case project through radially displaced holes around the circumference of the base of the case. Conveniently the tags would be of uniform length and could be cut when in position so that all tags project the same distance. As the space in the tube allocated for the capsule units is constant it the full number of capsule units is not required the vacant space can be taken up by a blank or blanks consisting of an outer annulus only and which will be inserted into the tube case prior to the insertion of the capsule units.

A circular operating plate l9 (Figs. 1 and 3) and the operating rods and 2| (Figs. 1 and 3) are next dropped into position. These comprise simple resinous mouldings, the former transmitting the pressure of the operating rods in response to an operation of the relay armature to the central pillars [5 of the capsules and being held in place simply by this pressure and by location within the outer case Ill. The operating rods are passed through holes in inwardly projecting members of the moulded case shown in Fig. 4.

The electromagnetic operating element is now inserted in position. This comprises a winding 22 wound on a core 23 screwed or otherwise secured to or integral with a U shaped heel-piece 24. This element is kept in place as shown in Fig. 3 by an abutment of the moulded shell case which engages with the closed end of the U shaped heel-piece, While the top ends of the U limbs are each provided with a projecting lip which engages in recesses in the case Ill. When the heel-piece is pushed into position in the moulded shell it will be understood that the shell will be slightly distorted by pressing on the sides until it forms a slightly oval shape so as to enable the projecting lips to enter and position themselves opposite the recessed holes therein. When this has been done and the pres! sure is released, the heel-piece, and the winding core will remain locked in position substantially as shown in Fig. 3.

The magnetic disc-shaped armature 25 is now dropped in being supported by the rods 20 and 2! at a predetermined distance from the end of the core and the top cap II is pressed home to complete the assembly in which position it is secured by suitable sealing means; a centering spider. 26 or its equivalent is interposed between these two items to hold the armature against the rods 20 and 2|. When the winding is energised the armature is attracted to the heel-piece and winding core and in so doing displaces the operating rods 20 and 2| to the left as seen in Fig. 3. This movement is communicated via the pressure plate l9 to the central pillars of the grou of capsules, and when these are moved relative to the outer rings the various spring combinations will be operated.

On de-energisation of the winding the pressure exerted by the displaced contact springs in the various capsules together with the pressure exerted by the distorted diaphragms operate to restorethe operating rods and in turn the armature to the normal position shown in Fig. 3.

In a preferred construction, the members I! are provided with recesses on one side and bosses on the other, the boss of one member fitting neatly into the recess of the other member whereby the capsules are centrally located with respect to each other, the face of the disc I! opposite the end capsule is fitted with a recess or boss to engage with the boss or recess of the pillar E5 of the end capsule. On the opposite face are two recesses into which the ends of the rods 20 and 2! are adapted to be fitted preierably in such a way that the rods are supported during assembly in an upright position independently of any support from the wall of the casing so that after the electromagnet is placed in position, and the armature, the other ends of the rods 20 and 2i will readily enter into recesses in the race of the armature. The armature in turn is supported centrally by the spider and consequently the whole movement of the armature and connecting rods and pillars I5 can be efiected without any sliding or rubbing action.

Although a method of electrical connection to the winding is not shown it will be understood that this can be effected in a similar manner to that involved in making connection to the capsules by providing contact tags supported and insulated in the U shaped heel-piece and passing through one pair of slots in the casing I 0 as shown in Fig. 2'. It will be moreover noted from reference to Fig. 1 that two threaded holes are provided, which extend part way through the closed end of the container, these holes being provided for the purpose of securing the relay to the mounting plate. Alternatively the tags could be arranged to engage springs in a holder so as to permit of ready interchange.

It will have been noted that no screws are required in the relay assembly, and this operation is therefore rendered very simple. The provision of an over-all cover on the relay for all component parts thereof provides immunity from dust troubles and obviates the necessity for provision of separate covers either on an individual or group basis. The use of a moulded tube form of exterior case enables a number of relays when mounted on a base plate to present a very neat appearance owing to the absence of projecting parts. The metallic parts on the relay are small in number and are simple in construction; the main bulk of the relay, which comprises insulated moulding materials,- can be produced in quantity at a very low cost making the relay cheap to manufacture.

An advantageous feature of the relayis that when it is to operate under straightforward nonmarginal conditions no adjustment whatever should be necessary after assembly. In thecases where the relay has to meet reasonably widely spaced operate and non-operate current values, or where it has t have controlled slow-to-operate or slow-to-release times in which case a copper slug will be provided, then any of the known forms of air gap control can be incorporated on the armature plate.

While it is expected that the relay will meet most of the present day circuit requirements it is appreciated that some special consideration will have to be given to special requirements such as obtain in the case of impulsing relays, marginal relays, polarised relays, and so on.

The relay as already outlined provides a completely dust-proof construction; but in circumstances where the contacts have to operate under onerous circuit conditions it may prove desirable to evacuate one or more of the capsules or even to evacuate such capsules and afterwards inject into them an inert gas. A further alternative to which the design according to the invention particularly lends itself, is to seal the connecting wires in the bottom of the tube and to seal the top cap in position and it would then be possible to evacuate the whole relay and then to inject an inert gas, instead of dealing with the separate capsules.

This would give two advantages in addition to simplifying the capsule construction, firstly, that no plating or other protection would be required on the metallic parts of the relay as these parts would be completely protected from adverse climatic conditions, while the capsules themselves need not be made closed units as described and in fact could be provided with one diaphragm only thereby simplifying manufacture thereof.

If the central pillar members of the capsules are arranged to interlock with one another as described above by providing bosses on one side and recesses on the other the operating emciency is further increased by assuring the formation of a continuous operating pillar when the capsules are assembled within the relay case. Again if a simple metal spider spring such as is shown in Fig. 7 be interposed between the armature 25 (Fig. 3) and top cap H, and designated 26 in this figure, the armature could be held central without rubbing on the sides of the tube and thereby introducing friction during its operatin movement. Referring to Fig. 7, tongues a could be bent forward to seat in recesses in the armature and tongues "17 could be bent backwards to seat into recesses in the top cap, the ends of the tongues have a sharp bend into the recesses so as to restrict lateral movement of the armature.

If a casing is provided for the whole relay the construction of the separately detachable units of the contact springs or a single unit should not be of cylindrical form but only approximately so, such as of horse-shoe shape so as to leave a gap in the periphery through which the actual contacts of the springs and their movement could be observed. The contacts springs may themselves be so shaped as to bring the contacts into the gap and therefore nearer the periphery.

It should also be understood that it is not es-- sential although highly desirable that the tube should be cylindrical. A hexagonal, octagonal or even a square section may be satisfactory for a range of relays but the cylindrical shape with freedom to insert the contact spring combinations at a large variety of angles would seem to be the best for general use unless of course special provision is made for dealing with the leading in tags.

What I claim as new and desire to secure by Letters Patent is:

l. A contact spring assembly for use in an electric switching device, comprising a plurality of independently assembled units each including a contact spring sub-combination and an operating member for that sub-combination, all of said contact spring sub-combinations cooperating to form a single major spring cbmbination, and all of said individual operating members cooperating to form a rigid unitary control device for operating said major spring combination as a single unit.

2. A contact spring assembly for use in an electric switching device, comprising a plurality of pre-assembled units each including a sprin combination and an operating member for that combination, said units so assembled with respect to one another as to bring the individual operating members into physical engagement one with another, thereby to cause a movement of one of said operating members to be communicated by that member to the others of said operating members.

3. A contact spring assembly for use in an electric switching device, comprising a tubular casing. a plurality of pre-assemblecl contact spring sub-combinations inserted in said casing and held in a superposed relationship by the interior walls of said casing, thereby to form a single major spring combination, and means for at all times insulating the adjacent ones of said spring sub-combinations from one another, thereby to permit the different spring sub-combinations to control different circuits.

4. In combination; a plurality of unitary structures each including a support, an electrical contact set mounted on said support and a member mechanically linked to said contact set for operating same; means for rigidly mounting said support in a fixed physical relationship to one another, said relationship being such that said operating members are in series; means for applying a force directly to the end of said operating members and, through it, to the remainder of said operating members, thereby to move all of said members and hence operate all of said contact sets.

5. In combination; a plurality of unitary structures each having a stationary supporting member, an electrical contact spring combination supported on said stationary member, and a movable operating member for said contact spring combination also supported on said stationary member; means for mounting said unitary structures in superposed relation so that their individual operating members are in alignment and so that there is no space between adjacent ones of said operating members; and means for moving the end one of said operating members in a direction toward the other end one of said operating members, thereb to move all of said operating member as a unit and hence operate all of said contact spring combinations substantially at once.

6. In combination, a plurality of separately formed annular rings each carrying a centrally disposed member, each of said members enjoying a limited movement in an axial direction with respect to its associated ring, an individual electrical contact spring assembly carried by each of said annular rings and operated by the member associated with that ring upon said movement thereof with respect to said ring, means for superposing said rings to form a substantially continuous cylinder, whereby said members are also superposed to form a substantially continuous column within said cylinder, and means for applying a force to the end one of said members to cause said column of members to move axially within said cylinder substantiall as a unit.

'7. In a switching device, a plurality of rings of insulating material, a set of spring contacts in each ring having their contact points within the ring, an operating bushing for each set having the same thickness as the ring and also lying within the ring, said rings assembled in a. pile with each ring supporting an adjacent ring and each bushing in contact with the bushings oi adjacent rings whereby pressure applied to an errd one of said bushings causes movement of all bushing in the pile and consequent operation of all of said sets of contacts.

8. In combination, a plurality of individual tubes superposed to form a single substantially continuous tube, a plurality of thin flexible walls each covering the end of one of said individual tubes, thereby to divide said continuous tube into a plurality of separate enclosures, means for applying a force along the axis of said continuous tube to one of said flexible walls to distort said one wall, means controlled by said force for thereupon distorting the others of said flexible walls, an electrical contact spring combination within each of said separat enclosures, and means controlled by said distorting of said flexible walls for operating said contact spring combinations.

9. A combination as claimed in claim 8, wherein each of said flexible walls is formed integrally with one of said individual tubes.

10. In a switching device, a plurality of cells each enclosing a set of contact springs, each cell having rigid side walls and flexible end walls, said cells arranged in a pile supported by the rigid side walls, means for applying a force on the flexible walls of an end cell, said force when so applied causing consequent movement of the flexible walls of all the cells and consequent operation of all contact sets.

11. In combination, a plurality of capsules each formed wholly of insulating material, a different electrical contact set completely enveloped by each of said capsules, means for applying a force to the wall of one of said capsules, and means responsive to the application of said force for operating all of said contact sets.

12. In combination, a plurality of hermetically sealed capsules formed wholly of insulating material, each of said capsules enclosing an electrical contact set, mean for applying a force to the wall of one of said capsules, and means operated by said force applied to the Wall of said one capsule for operating all of said contact sets.

13. In combination, a plurality of capsules each ubstantially enclosing an electrical contact set, means for applying a force to the Wall of one of said capsules, and means in each of said capsules operated responsive to the application of a, force to a wall of that capsule to operate the contact set within said capsule and to apply a force, independently of said contact set, to the wall of a particular other one of said capsules.

14. In a relay, a plurality of separate enclosures, an electrical contact set for each enclosure, each contact set supported by its associated enclosure and having at least one contact movable within the space generally defined by said enclosure, a movable member for each enclosure, each member supported by its associated enclosure and efiective, when moved, to move said movable contact within that enclosure, means for moving one of said members, and means for mounting said enclosures in fixed relationship to one another in such a way as to mechanically connect said members, thereby to cause said one member, when moved, to move the others of said members.

15. In a relay, a plurality of interchangeable rare-assembled contact spring combinations, an electromagnet, and an armature for operating said contact spring combinations, said spring combinations, said magnet and said armature all enclosed within a casing molded of insulating material and held in a predetermined relationship to one another by said casing.

16. In a relay; a plurality of interchangeable pre-assembled units each including a contact spring combination and a member for operating that combination; an electromagnet; an armature controlled by said electromagnet for moving said operating members; and a casing enclosing said units, said electromagnet and said armature and holding said units and said electromagnet in a predetermined relationship to one another.

17. A relay as claimed in claim 16, wherein said casing is hermetically sealed.

18. In a relay, a tubular casing, a plurality of pre-assembled contact spring sub-combinations inserted in said casing and held in superposed relationship by the interior walls of said casing, thereby to form a single major spring combination, a plurality of longitudinal recesses in the interior wall of said casing, each of said contact spring subcombinations having associated conductoIS lying in said recesses and accessible from outside said casing, an electromagnet within said casing and an armature within said casing controlled by said electromagnet for operating said major spring combination essentially as a unit.

19. In a relay, a plurality of capsules each enclosing an electrical contact set, a casing enclosing said capsules and holding same in a superposed relationship, an electromagnet, an armature controlled by said electromagnet to apply a force at times to a wall of the top one of said capsules, each of said capsules having means controlled by the application of a force to its wall for operating the contact set within that capsule and applying a force, independently of the contact set within that capsule, to a wall of the next capsule below itself.

20. A relay as claimed in claim 19, whereln said electromagnet is also enclosed within said casing and held by said casing in a predetermined relationship to said capsules,

21. A relay structure, comprising a hollow tube, an electromagnet within said tube and restrained by the interior walls thereof against movement in a direction transverse to the axis of said tube, an armature within said tube controlled by said electromagnet to move in an axial direction with respect to said tube, a plurality of contact spring combinations within said tube, said combinations spaced at intervals alon the length of said tube, and means controlled by said axial movement of said armature for operating all of said contact spring combinations.

22. In a relay structure as claimed in claim 21, means substantially closing the ends of said tube to prevent the entrance of foreign matter thereinto..

GEORGE THOMAS BAKER. 

